What Causes a Rich Fuel System?

[AmaraFitz]

Reasons for a rich fuel system: 1. Slight leakage in the fuel injector leads to a high fuel-air mixture ratio in the engine. This can be caused by minor injector leakage, failure of the water temperature sensor, or potential faults in the air flow meter and oxygen sensor. 2. Insufficient engine cylinder pressure results in a low compression ratio. This can be detected by listening to the engine's performance or measuring cylinder pressure. Low cylinder pressure is usually due to mechanical issues such as problems with the pistons, rings, cylinders, or valves. 3. Spark plugs with carbon deposits cause weak high-voltage sparks. This is due to spark plugs having carbon buildup, small gaps, poor performance, or issues like leakage and misfiring.